The document discusses reactive architectures with microservices. It defines reactive architecture as being asynchronous, non-blocking, loosely coupled, and push-based. It recommends building reactive systems on AWS using services like ECS, Lambda, Kinesis, ElastiCache and DynamoDB. The application architecture described uses Vert.x and microservices like HTTP, caching and Redis Verticles. Global rollout is discussed, noting the options of a master region or distributed processing across regions using CloudFormation for infrastructure as code.

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Sascha Möllering, Solutions Architect, @sascha242
07.11.2017
Reactive Architectures with
Microservices

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https://secure.flickr.com/photos/mgifford/4525333972
Why are we
here today?

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Agenda
• What is Reactive Architecture?
• How to build Reactive Architectures in AWS?
• Application Architecture
• Global Rollout
• Q&A

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What is Reactive Architecture?

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Front-end
server
Internal
API
Internal
APIAPI
Poll
Poll
Database
Storage
Queries
Synchronous
User waits
for update
N-Tier architecture

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Software moves
faster today

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Traditional style of
applications cannot deliver
on these requirements any
longer

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Responsive
Elastic Resilient
Message-driven
Reactive Applications

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Reactive programming
“A development model focusing
on the observation of data
streams, reacting on changes, and
propagating them”
Reactive Architecture
Reactive system
“An architecture style used to
build responsive and robust
distributed systems based on
asynchronous message-passing.”

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Reactive Architecture
• Asynchronous message passing
• Non-blocking
• Higher throughput
• Effective hardware utilization and lower costs
• Loosely coupled
• Location independent
• Easy to extend and maintain
• Push-based

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Microservices

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Microservices should be stateless.
Keep state in external systems.

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Avoid
Host-Affinity.

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Use lightweight
protocols for
communication.

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Use mechanisms for
registration.

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How to build Reactive
Architectures in AWS?

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Example use case
Banner
Icon made by Freepik from www.flaticon.com
Customer visits
website
Customer clicks
on a banner
Customer buys
from online-shop

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High Level Architecture

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Amazon ECSApplication
Load Balancer
Amazon ECR
Kinesis
Stream
Kinesis
Stream
Lambda
function
Lambda
function
ElastiCache
cluster
Data ingestion
Core data
update
Amazon
DynamoDB
Core data updates
Data collection

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High Level Architecture
• Amazon ECS and Docker used for the main
application
• Resiliency and Elasticity implemented by
using Auto Scaling

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High Level Architecture
• AWS Lambda functions
• Consume messages
• Persist data in NoSQL-store
• Update core-data in Redis
• Send notifications to main application
• Resiliency and Scalability part of the service

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High Level Architecture
• Amazon Kinesis Streams used to decouple
components
• Asynchronously push event data to NoSQL-
store
• Update core-data in Redis

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High Level Architecture
• Amazon ElastiCache with Redis 3 engine
• Multi-AZ setup with failover and one shard
• Used to store core-data
• Notification channel
• Redis supports pub/sub

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High Level Architecture
• Amazon DynamoDB NoSQL-store used to
persist event-data

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Application Architecture

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Amazon ECSApplication
Load Balancer
Amazon ECR
Kinesis
Stream
Kinesis
Stream
Lambda
function
Lambda
function
ElastiCache
cluster
Data ingestion
Core data
update
Amazon
DynamoDB
Core data updates
Data collection
You are here now!

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Application Architecture

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Application Architecture
Picture source: http://vertx.io/docs/guide-for-java-devs/

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Application Architecture
“Don’t block the event
loop!”
- Vert.x golden rule

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Application Architecture
Picture source: http://vertx.io/docs/guide-for-java-devs/

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Application Architecture
Picture source: http://vertx.io/docs/guide-for-java-devs/

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Application Architecture
• HttpVerticle: exposes HTTP endpoint
• CacheVerticle: implements L1 cache
• RedisVerticle: implements Redis access
• KinesisVerticle: messages to Amazon Kinesis Stream

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Subscribe to EB
Send prepared data

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Application Architecture
Cache
Rules
Everything
Around
Me

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Subscribe to EB
Subscribe to
Redis channel
Consume data
from event bus
Send data to
cache verticle

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Amazon ECSApplication
Load Balancer
Amazon ECR
Kinesis
Stream
Kinesis
Stream
Lambda
function
Lambda
function
ElastiCache
cluster
Data ingestion
Core data
update
Amazon
DynamoDB
Core data updates
Data collection You are here now!

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Application Architecture
AWS Lambda

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Lambda considerations and best practices
AWS Lambda is stateless—architect accordingly
• Assume no affinity with underlying compute
infrastructure
• Local filesystem access and child process may not
extend beyond the lifetime of the Lambda request

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Kinesis event
processing
Iterate over
batch of events

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Global Rollout

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16 Regions
44 Availability Zones
AWS Global Infrastructure

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Global Rollout
AWS CloudFormation

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Global Rollout
• Infrastructure as Code
• Create and manage resources with CloudFormation
templates
• CloudFormation template is used to deploy stacks

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Global Rollout

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Master Region
• One stream of data
• One region to process data
• Data has to be transferred
inter region
Global Rollout
Distributed Processing
• Data processing in every
region
• No unified view on data

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Summary

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Summary
• Reactive Architectures very good fit for AWS Cloud
• Microservices improve isolation
• AWS offers a lot of services for decoupled application
design
• Focus on business requirements, don’t reinvent the
wheel

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Thank you!